Abstract/Description

Practically all irrigated rice in sub-Saharan Africa is prone to the rice yellow mottle virus (RYMV). Until the 1990s, the effects of RYMV were relatively modest but since then yield losses of up to 95% have occurred throughout the continent s rice...

Notes

Practically all irrigated rice in sub-Saharan Africa is prone to the rice yellow mottle virus (RYMV). Until the 1990s, the effects of RYMV were relatively modest but since then yield losses of up to 95% have occurred throughout the continent s rice fields. The disease is carried by beetles and spreads easily. It causes yellowing (or orange discoloration) of the leaves hence its name and leads to sterility of the flowers, stunted growth and poor panicle exertion, or stalk development.
From 1995 to 2001, a group of researchers in the Irrigated Rice Programme of the Institute for Rural Economy (IER) in Mali studied how RYMV spreads. They came up with a set of measures to control and prevent infections. This, and other results, won the programme s coordinator, M Baré Coulibaly, the National Scientist Award for his 'outstanding contribution to the development of rice cultivation in Central and West Africa', given for the first time in April 2002 by ROCARIZ, WARDA and WECARD. His finding was that susceptibility differs at various stages in the rice plant s development. Burning infected plant material, ploughing infected fields just after harvest and before the next cropping season and flooding the field are but a few of the proposed control measures. The virus is spread through manual contact with infected plant material but also by footwear and by tractors, farm implements and animals such as rats and livestock. Farmers should therefore, besides washing hands and shoes, avoid double cropping and weeding in contaminated fields and should not leave cattle in these fields overnight. Keep rats out of the fields and keep canals, roadsides and levees as clean as possible, the research group advises.
[caption to illustration]
Golden Orb spiders, Golden Orb flowers, and now golden orb virus
CRRA de Niono, Institut d Économie Rurale Programme Riz Irrigué
BP 12, Niono, Mali
Email: crra.niono@ier.ml